We have recently acquired The Hemox Analyzer which enables automatic recording of oxygen equilibrium curves of whole blood and isolated hemoglobins. This system will be utilized in determining: 1) Oxygen equilibrium curves as well as the determination of a number of important and relevant variables such as hemoglobin cooperativity, Boher effect, temperature effect, etc. for a number of chemically modified hemoglobin preparations. 2) Whole blood oxygen equilibrium curves in samples from adult sickle cell patients undergoing treatment with a combination therapy of recombinant erythropoietin and hydroxyurea. The effect of increased fetal hemoglobin synthesis ( a result of EPO/HU administration) on oxygen binding characteristics of the intraerythrocytic hemoglobin S will be determined. This specific part of the project will be carried out here at our lab in collaboration with Drs. G. Rodgers and A Schechter from the Lab of Cell Biology, NIDDK, Bldg. 10.